Tears of the Subscapularis Tendon in Athletes

Tears of the SubscapularisTendon in AthletesçDiagnosis and RepairTechniques

a b, Dana P. Piasecki, MD , Gregory P. Nicholson, MD *

KEYWORDS Subscapularis Repair Tendon Tears Diagnosis

Isolated injury to the subscapularis tendon is an uncommon—but potentially debilitating—injury among athletes. The most frequent injury pattern seen in younger athletes is an acute, traumatic tendon avulsion. In the older athletic population, chronic degenerative tearing of the tendon may precede sports-related rupture, particularly after shoulder dislocation. This article reviews how to diagnose this injury in athletes and describes both conservative and operative treatment options and their outcomes. Although a growing body of literature has come to recognize isolated subscapularis tendon tears in a typically nonathletic population, little has been written on the analo- gous pathology in active, athletic patients. Injury to this portion of the rotator cuff, however, does occur, with clinical implications ranging from diminished athletic per- formance to serious disability. Familiarity with the potential injury patterns in an athletic population as well as an understanding of the diagnostic workup and appropriate treatment considerations are important to the practicing orthopedist.

ANATOMY The subscapularis muscle–tendon unit comprises the anterior rotator cuff, providing active internal rotation of the humerus and contributing to the dynamic anterior stabil- ity of the glenohumeral joint. Nervous innervation is provided via the upper and lower subscapular nerves and their variable branches that enter the muscle belly medial to the conjoint tendon.1 The muscle belly originates on the medial two thirds of the scap- ular body, developing a tendinous character at the more lateral joint line and inserting at the lesser tuberosity in coalescence with the anterior shoulder capsule.2 At the joint

a Division of Orthopaedic Sports Medicine, Midwest Orthopaedics at Rush, Rush University Medical Center, Suite 1063, 1725 West Harrison Street, Chicago, IL 60612, USA b Division of Orthopaedic Sports Medicine and Shoulder and Elbow Surgery, Midwest Orthopaedics at Rush, Rush University Medical Center, Suite 1063, 1725 West Harrison Street 1063, Chicago, IL 60612, USA * Corresponding author. E-mail address: [email protected] (G.P. Nicholson).

line, subscapular and subcoracoid bursae lubricate the muscle–tendon’s articulation with the more posterior joint capsule and anterior coracoid process, respectively.3 The tendon has its greatest bulk superiorly, tapering off to a thinner, more muscular layer inferiorly.2 The dimensions of the bony insertion follow this theme, with a wider superior aspect (1.8–2.0 cm from medial to lateral) that thins toward the bottom of the lesser tuberosity (mean, 0.3 cm medial to lateral width), creating a trapezoidal insertion whose greatest dimension is its vertical lateral edge (2.5–4 cm from proximal to dis- tal).4–6 The tendon’s insertional fibers also extend posteriorly and laterally over the top of the bicipital groove, coalescing with insertional fibers of the supraspinatus—as well as the coracohumeral (CHL) and superior glenohumeral (SGHL) ligaments—to form the biceps pulley complex, performing an important stabilizing role for the biceps tendon.7,8 Biomechanically, the superior and midportions of the tendon have substantially greater stiffness and ultimate load to failure than the tendon’s inferior portion, providing a measure of protection against propagation of cuff tears superiorly but theoretically posing a region of vulnerability to anterior shoulder dislocation inferiorly.9

PATHOPHYSIOLOGY Acute, high-energy sports-related events are the most commonly reported mechanism of subscapularis tears in athletes. Among sports as varied as waterskiing, baseball, and arm wrestling, several investigators have reported either partial or complete tendon rupture after a typically violent hyperextension or combined adduction and external rotation maneuver.10–12 In skeletally immature athletes, in whom the physes are generally weaker than musculotendinous or tendinous tissues, similar mechanisms may instead cause frank lesser tuberosity bony avulsions.13–17 In older athletes, the tendon usually ruptures first and with generally lower energy events. Particularly among athletes older than 40 years, the prevalence of pre-existing degenerative, partial-thickness articular-sided fraying18–20 may weaken the tendon at its insertion, increasing the likelihood of full-thickness rupture during less-violent sporting activities.21–23 Similar age-related differences are seen after shoulder dislocations, in which younger patients typically present with a Bankart lesion, whereas older athletes are much more likely to suffer full-thickness rotator cuff tears—particularly of the subscapularis.24 Chronic overuse-related microtrauma and tendon degeneration may play an important role in predisposing athletes to traumatic rupture, particularly in older age groups. Several investigators have hypothesized that the tendon may be chronically injured by a mechanical compression between the lesser tuberosity and coracoid process25–27—the so-called ‘‘roller wringer effect’’—of particular significance in high-demand overhead athletes.28 Another contributory mechanism of injury is anterosuperior impingement, in which articular-sided abrasion may occur at the lesser tuberosity and glenoid rim interface, especially in the resisted flexed and internally rotated positions (eg, the tennis follow-through).29,30 Such chronic, repetitive stress applied to the subscapularis musculotendinous junction could lead to microtrauma and eventually macroscopic tendon compromise.23,28,31 Whether sport-specific activities predispose to such chronic overuse is not yet clear, although several studies have demonstrated tremendous subscapularis demands during certain sports. EMG analysis of golfers, for instance, suggests that the subscapularis dominates all other muscle activity during the golf swing, making it vulnerable to injury.32 Similar investigation has shown tremendous subscapularis demands during the tennis serve and forehand stroke,33 with a high frequency of ultrasound-confirmed subscapularis tendon calcifi- cations in the dominant shoulder of veteran (age, 35–77 years) tennis players.34 MRI of amateur baseball pitchers’ throwing shoulders has demonstrated significant increases

EPIDEMIOLOGY Isolated subscapularis tears in athletes are probably quite rare—particularly among young athletes—although the true incidence of these lesions is not currently known. The only published reports of these injuries in active patients younger than 40 years are small case series or case reports. Although the literature on older age groups is largely limited to degenerative tears, several studies suggest that sports-related tears are likely to be more common in older athletes. Although activity level was not spec- ified, Flury and colleagues39 reported isolated subscapularis tendon tears in 3% of their series of 1345 symptomatic rotator cuff repairs (mean age, 56 years) and Sakurai and colleagues18 noted a 13% rate of presumptively asymptomatic partial-thickness degenerative tears in their cadaveric study, suggesting that degenerative tears may occur with some frequency in these patients. Where reported, sports-related tears in older athletes tend to occur with less violence than in younger patients, and in association with degenerative tendons.21–23 Likewise, the association of these tears with shoulder dislocations24—as not infrequently occurs during contact sports—suggests that older patients may be expected to suffer sports-related subscapularis tears more frequently than their younger counterparts.

DIAGNOSIS History A careful history should be obtained in all athletes presenting with shoulder pain and/or weakness. Specific to subscapularis injury, the time-course and mechanism of injury should be sought. Particularly in younger patients, subscapularis injury will typically follow a significant acute trauma in which the arm is forcibly hyperextended and/or externally rotated, although the diagnosis may be delayed.12,40 Older patients may report pre-existing mild pain in the anterior aspect of the shoulder (ie, from symptomatic partial-thickness degenerative tears) with a dramatic worsening of pain and internal rotation weakness after a sports-related dislocation or maneuver in which the subscapularis is overstressed (eg, tennis serve follow-through or high-speed pitching).22,23 Symptoms at the time of presentation typically involve anterior shoulder pain—occa- sionally with radiation to the forearm—during use of the arm both above and below shoulder level and at night.12,40 Most of the patients will also note subjective upper extremity weakness.12 Given the stabilizing role of the subscapularis, patients should also be questioned about subluxation or dislocation events and any subsequent sense of instability.40 In older patients, the high association of subscapularis tears with tears of other rotator cuff tendons and/or the biceps pulley complex warrants focused ques- tioning in these areas as well. These findings are summarized in Table 1.

Physical Examination The involved upper extremity should be inspected for signs of trauma, and a thorough physical examination performed with special attention directed toward range of

Table 1 History findings in supscapularis tendon tear

Mechanism Younger (<40 y) athletes: forced hyperextension or external rotation Older (>40 y) athletes: preceding symptoms, often lower energy acute event (eg, throwing or dislocation) Symptoms Anterior shoulder pain With activity above and below shoulder level At night Subjective weakness in internal rotation, overhead activities Subjective instability

motion, rotator cuff strength, instability, neurovascular status, and potentially coexis- tent biceps pathology. Most of the patients with isolated subscapularis rupture will present with tenderness over the lesser tuberosity,40 increased passive external rotation, slightly diminished internal rotation strength, and a positive bear-hug,41 belly- press,42 or lift-off12 test. Partial tears of the upper subscapularis may first present with only a positive bear-hug test because of this maneuver’s greater sensitivity in detecting smaller tears.41,43 Likewise, because the lift-off test preferentially evaluates the lower portion of the muscle–tendon complex44 and tears tend to propagate from superiorly to inferiorly this test is not typically positive unless tears exceed roughly 75% of the insertion.41 Some investigators have also reported a frequently positive Jobe supraspinatus test21 in isolated subscapularis tears, probably because of a relative force couple imbalance about the anterosuperior aspect of the humeral head. A significant number of patients may also have a positive apprehension sign12,20 during instability testing, and provocative biceps findings (Speed and Yergason’s tests) are also commonly reported.22,40 In older patients, coincident tears of the other rotator cuff tendons may present with positive impingement signs or weakness in forward elevation.20 Common physical examination findings are shown in Table 2.

Imaging Routine plain films (anterior/posterior [AP] and axillary views) \should be obtained in all patients suspected of having subscapularis tendon ruptures. Although these images

Table 2 Physical examination findings in subscapularis tendon tear

Inspection Signs of trauma and possible cuff atrophy (older patients) Palpation Tenderness over lesser tuberosity and bicipital groove Range of motion Increased passive external rotation with arm at side Strength Weakness in resisted internal rotation Provocative testing Positive lift-off Positive belly-press Positive bear-hug Positive Jobe supraspinatus test

Downloaded for Anonymous User (n/a) at Rush University from ClinicalKey.com by Elsevier on December 31, 2018. For personal use only. No other uses without permission. Copyright ©2018. Elsevier Inc. All rights reserved. Diagnosis and Repair Techniques 735 will usually be normal,12,40 an associated greater45 or lesser tuberosity avulsion frac- ture14,46 may be evident on a radiograph, particularly in skeletally immature athletes. Although lesser tuberosity fractures are often best visualized on the axillary view, an internally and/or externally rotated AP view often adds to the visualization of the tuberosity portion of the humeral head, and these views are also frequently obtained. A narrowed acromiohumeral interval in older patients may indicate an associated massive rotator cuff tear.47 In all patients, plain films should be used to identify any joint space narrowing and to confirm that the glenohumeral joint is located. Several other imaging methods are available to assess subscapularis tendon integrity. Ultrasound may be useful in patients suspected of having large subscapularis tears, although this modality is highly operator-dependent and less likely to visualize and/or quantify smaller, partial-thickness tears.48 CT arthrograms may also be used for detection of subscapularis tendon tears—isolated tears typically associated with contrast extravasation from the glenohumeral joint onto the lesser tuberosity21—but are limited in visualizing associated biceps and rotator cuff pathology. MRI is the imaging modality of choice in patients suspected of subscapularis tendon injury.40 Isolated subscapularis muscle strain can be appreciated as increased muscle belly signal on T2-weighted images.36 Partial-thickness11,18 tears are also visualized as loss of T1 signal and increased T2 signal on axial images at the tendon’s lesser tuberosity insertion, typically on the articular side. Full-thickness tears are readily visualized as tendon discontinuity at or near the tuberosity insertion,40 with a high frequency of focal periarticular fluid in the superior subscapularis recess49 and associated biceps tendon subluxation or dislocation (Fig. 1).50 Sagittal oblique images may be particularly helpful for appreciating both tendon discontinuity and retraction (Fig. 2).49,50 The examiner should also carefully evaluate the status of the subscapularis muscle belly. Chronic tears may show significant fatty degeneration,51,52 which is also easily quantified on MRI. Despite the usefulness of MRI for imaging these tears, the above findings may be frequently overlooked by radiologists,49 and may be further complicated in overhead athletes—who may have pre-existing asymptomatic rotator cuff lesions.53 A summary of pertinent imaging findings is given in Table 3.

Fig. 1. MR image (axial cut) demonstrating (A) normal subscapularis tendon appearance, compared with (B) increased T2, decreased T1 signal at the subscapularis insertion, and a medially dislocated biceps tendon which accompanies a tear. (From Tung GA, Yoo DC, Levine SM, Brody JM, Green A. Subscapularis tendon tear: primary and associated signs on MRI. J Comput Assist Tomogr 2001;25(3):417–24; with permission.)

Fig. 2. Sagittal oblique MRI cuts may also be useful in visualizing the subscapularis insertion. (A) Normal insertion compared with (B) the increased signal (straight solid arrow) on this T2-weighted image involving a partial tear of the cranial portion of the insertion (curved arrow, intact supraspinatus; unfilled straight arrow, intact caudal subscapularis insertion.) (From Tung GA, Yoo DC, Levine SM, Brody JM, Green A. Subscapularis tendon tear: primary and associated signs on MRI. J Comput Assist Tomogr 2001;25(3):417–24; with permission).

Arthroscopy In cases where the history, physical examination, and imaging studies are inconclu- sive, a diagnostic arthroscopy may be necessary to confirm subscapularis tendon injury. During a standard diagnostic arthroscopy, the upper rolled edge of subscapularis tendon and its insertion into the lesser tuberosity can be viewed with the scope in the posterior portal and the arm forward flexed and internally rotated (Fig. 3). Further increasing forward elevation from 60 to 90 enhances visualization of the undersurface of the tendon adjacent to the lesser tuberosity, and allows it to be probed through the anterior portal.54 Given the frequent association of subscapularis tears with cuff and biceps pulley complex pathology, particular attention should also be paid to these structures during arthroscopy. Although only the upper 25% of the subscapularis tendon and its insertion can be viewed from within the joint,55 this region is the most structurally significant9 and most frequently injured.18 Should additional visualization be necessary, viewing the footprint with a 70 lens from the posterior portal is

Table 3 Imaging Findings for SubscapularisTendonTear

Radiograph (AP, axillary) Usually normal (to rule out fracture, dislocation, arthrosis) Evaluate acromiohumeral, CHL intervals Ultrasound Tendon discontinuity (including intrasubstance tears) CT arthrogram Dye on the lesser tuberosity MRI Decreased T1 and increased T2 signal at insertion Focal periarticular fluid in subscapularis recess Evaluate tendon retraction and degree of fatty infiltration Evaluate biceps tendon subluxation/dislocation Evaluate remaining rotator cuff

Fig. 3. Arthroscopy. With the scope in the posterior portal of the right shoulder, the retracted stump of a full-thickness subscapularis tendon tear (SSc) and dislocated biceps tendon (B) are immediately evident. HH, humeral head; G, glenoid. effective. Some investigators have described visualizing the entirety of the extra-articular portion of the tendon via the subacromial space (with the scope in the lateral portal).56

CLASSIFICATION The most common classification scheme for subscapularis tendon tears is descrip- tive,20 noting whether the tear is of partial or full thickness and whether it involves only a portion or the entirety of the insertion. Full-thickness, complete tears are also described in relation to the degree of retraction. Associated tears of the SGHL and CHL as well as the remaining rotator cuff tendons should also be noted.57 Pfirrmann and colleagues58 have also proposed an MR classification scheme, denoting grade 1 tears as those involving less than 25% of the craniocaudal tendon, grade 2 tears as those involving more than 25% but without complete detachment, and grade 3 tears as those with complete detachment.

TREATMENT Nonoperative Treatment Given the functional disability and long-term clinical implications of delayed surgical management of full-thickness tears,39 conservative management of athletic subscapularis tears should be reserved for isolated, partial-thickness lesions. Particularly in older athletes with tendonopathy and/or partial tears—which may be incidental to other nonsurgical causes of shoulder pain—a trial of rest, activity restrictions, physical therapy, and anti-inflammatory medications may be considered for up to 3 months. A similar nonoperative approach has also been used successfully in treating nondisplaced lesser tuberosity fractures.15 An initial nonsurgical approach may additionally be considered in patients presenting with select chronic, full-thickness tears that are either minimally symptomatic or impaired and/or have a high likelihood of failure after primary repair. For complete, retracted tears older than 1 year and/or with stage 3 or greater fatty degeneration51 and/or associated rotator cuff arthropathy, the substantial risk for failure39 may warrant a course of nonoperative treatment in lieu of

pectoralis tendon transfer or other salvage procedures; this is especially relevant in older, less demanding patients. Continued pain and/or functional limitation after nonoperative treatment in any patient warrants consideration for operative intervention.

Operative Treatment Patients with partial-thickness tears failing nonoperative treatment—and those with full-thickness tears— require surgery to relieve pain and restore shoulder function. In the case of full-thickness tears, surgery to repair the tendon at its insertion should not be delayed given the evidence of compromised outcomes in patients subjected to delayed repair.39,42 Most surgeons recommend repair within 1 to 2 weeks of presentation to avoid tendon retraction and scarring. The indications for debridement versus repair of partial-thickness tears in an athletic population are not yet clear in the literature. In the case of isolated partial subscapularis tears in athletes, the authors’ preferred approach is to attempt debridement in the majority of tears involving less than 50% of the tendon’s insertion, especially when pain, and not functional loss, is the primary complaint.59 After failure of nonoperative management, the authors prefer to fix partial tears involving more than 50% of the upper subscapularis insertion—particularly among athletes with any functional impairment and/or whose sports place considerable demands on the tendon given the theoretic risk this represents for later full-thickness tearing. Associated biceps tendon subluxation in the case of partial- thickness subscapularis tears poses a challenge; there is no consensus regarding whether the biceps should be preserved or tenodesed. The authors’ preference in this situation depends on the appearance of the biceps tendon. If the tendon is not frayed and degenerative, the authors have a lower threshold for fixing partial subscapularis tears and preserving the biceps tendon long head, recognizing that not all repairs will protect against subluxation. Although a case-by-case approach is used for biceps instability after such fixation, the authors find this problem is most reliably managed by the authors with biceps tenodesis. Displaced lesser tuberosity avulsion fractures are treated as full-thickness tendon tears. Debridement of partial-thickness tears can readily be accomplished through an arthroscopic approach, which preserves the bursal side of the tendon.60 With the arthroscope in the posterior portal and the arm elevated (to 45 or more) and internally rotated, the most common articular-sided tear pattern can be visualized. In this posi- tion, a probe can be introduced through the anterior interval portal and used to explore and quantify the degree of insertional compromise. A shaver introduced through the same portal can then be used to debride the frayed articular side of the tendon. The surgeon should simultaneously perform a careful evaluation of the SGHL and medial CHL portions of the biceps pulley complex, which are frequently injured in association with tears of the upper subscapularis tendon. Damage to these structures is often associated with a subluxating or dislocating biceps tendon and may influence treatment decision making, necessitating a biceps tenodesis.43 Repair of partial-thickness tears can also be accomplished using a similar setup. With the scope in the posterior portal, the articular side of the tendon and its upper rolled border can be gently debrided with a shaver introduced through a standard portal. A more medially based portal, however, permits direct access to the tuberosity, as well as easier targeting with suture passers when considering subscapularis repair.43 Debridement of the frayed tendon and overlying rotator interval tissue at the insertion facilitates accurate quantification of the degree of tendon compromise, although the surgeon should take care to preserve the SGHL and CHL contributions to the medial biceps pulley complex, if still intact. Medially, exposure of the coracoid process both increases the field of view and allows subsequent coracoplasty should this be

Downloaded for Anonymous User (n/a) at Rush University from ClinicalKey.com by Elsevier on December 31, 2018. For personal use only. No other uses without permission. Copyright ©2018. Elsevier Inc. All rights reserved. Diagnosis and Repair Techniques 739 indicated (Fig. 4).43 Coracoplasty is performed rarely in younger athletes with acute, traumatic presentations but may be a helpful adjunct in older athletes with prior subcoracoid impingement symptoms and an inferolaterally prominent coracoid process, prominent lesser tuberosity, and narrowed CHL interval.61,62 If a biceps tenodesis is planned, tenotomy at this stage of the operation will further facilitate exposure of the subscapularis insertion, although the authors generally make decisions about tenotomy after the subscapularis is fixed, particularly in overhead athletes in whom preservation of the biceps tendon is preferred. Bony preparation of the lesser tuberosity is performed in the region of tendon compromise with a burr from the anterior portal. An accessory anterosuperolateral rotator interval portal43 is then established using an 8.25-mm cannula as the principal working portal. Suture anchors can be introduced through the anterior portal and sutures then passed through the tendon using various tendon penetrating devices from the anterosuperolateral portal. To avoid obstructing one’s field of view, anchors and suture passage is generally performed from inferior to superior, with typically a double-loaded anchor per centimeter of repair.43 Knots are usually tied most easily through the anterosuperolateral portal with the arm in internal rotation. Full-thickness tears have traditionally been fixed through an open approach, although several arthroscopic repair techniques have been described. Arthroscopically, the technique is similar to that used for repair of partial-thickness tears (discussed ear- lier). However, full-thickness tears present a greater technical challenge given the frequent retraction of the tendon medially. Typically the upper corner of the tendon can be located by persistent attachment of the SGHL and CHL, which has he appearance of a ‘‘comma’’ (Fig. 5).43,63 Once the tendon is located in this manner, a traction stitch may be placed at the junction of the comma sign and the upper corner of the tendon; passed outside the anterosuperolateral cannula, these stitches may be used to apply traction to the tendon in a nonobstructive way.43 The tendon is then released of any adhesions, anteriorly and superiorly between the tendon and the coracoid, and, if necessary, posteriorly through the capsule to the anterior glenoid neck.43 Care must be taken to avoid any dissection medial to the coracoid process during the anterior and superior releases. Bony preparation and anchor insertion are then performed as for partial-thickness tears, with the traction stitch providing tendon reduction during suture passage.

Fig. 4. Coracoplasty. The coracoid is first exposed and then burred posteriorly to increase the space available for the subscapularis tendon.

Fig. 5. The ‘‘comma sign’’ is formed by residual attachments of the retracted tendon edge to the SGHL and CHL. In the figure (right shoulder), an asterisk marks this tissue and dotted lines mark the corner of the subscapularis tendon. G, glenoid; H, humerus. (From Lo IK, Burkhart SS. The comma sign: An arthroscopic guide to the torn subscapularis tendon. Arthroscopy 2003;19(3):334–7; with permission).

Open repair of isolated subscapularis tendon tears is typically performed through a standard deltopectoral approach (Fig. 6).64 A combined subscapularis and supraspinatus tear may be managed through a superior deltoid splitting exposure64,65 or a ‘‘hybrid’’ technique (arthroscopic supraspinatus repair followed by open subscapularis repair) so long as fluid extravasation is minimal before the open exposure. Even in cases where an open approach is planned, it may be beneficial to perform an initial diagnostic arthroscopy before open repair to assist in quantifying the degree of rotator

Fig. 6. Open repair. Exposure and repair of an isolated subscapularis repair is usually performed through a standard deltopectoral approach. After the development of the deltopectoral interval, satisfactory exposure is provided of the subscapularis insertion. A full-thickness subscapularis tear is seen through this approach (right shoulder). Repair may subsequently be performed using either suture anchors or transosseous sutures. SSc, subscapularis; HH, humeral head; bg, bicipital groove.

AFTERCARE Postoperatively, all patients are initially placed in a sling for protection. In cases where isolated partial tears are only debrided, full activities may be allowed once postoperative pain has subsided.60 In all repairs, the tendon must be protected for a minimum of 6 weeks. Although passive forward elevation and internal rotation are initiated immediately after surgery, passive external rotation is limited to the extent that the repair is not overly stressed, and limits should be determined in the operating room after repair. Active internal rotation and overhead motion is also prevented until after the 6-week period of protection.43 After 6 weeks, the sling is discontinued and end-range stretching in external rotation is advanced along with isometric strengthening exer- cises. At 3 months, below shoulder-level Thera-Band strengthening can be initiated and sport-specific activities started around 4.5 months. Return to play is predicated on the return of adequate motion and strength and usually occurs roughly 6 months postoperatively.

RESULTS No substantial studies have reported outcomes after debridement and/or repair of isolated subscapularis tendon tears in athletes. The available case report data suggest good-to-excellent outcomes for operative repair of athletic partial-11 and full-thick- ness22,40 tears, as well as nonoperative15 (nondisplaced) and operative16,17,67 management of lesser tuberosity avulsion fractures, with the vast majority of patients returning to full activities and/or their preinjury level of sport in 3 to 6 months. Deutsch and colleagues40 have reported excellent outcomes in a series of 13 patients (mean age, 39 years) after open repair of isolated full-thickness tears, with 12 of 13 patients returning to preinjury sports activities at mean 2-year follow-up. Larger series in pre- dominantly older patients (mean age, 60 years) echo these findings, with appropriately indicated arthroscopic debridement of partial tears producing high levels of patient

satisfaction and functional improvement.60 Similar results have been reported after arthroscopic68,69 and open42,66 repair of partial- and full-thickness tears. However, the latter outcomes do not include a return to athletic activity and for their older cohorts are difficult to relate to a younger, athletic population.

SUMMARY Subscapularis tendon tears are uncommon, but typically debilitating, injuries among athletes. Potential injury patterns range from overuse tendinopathy and/or partial tearing to complete bone–tendon avulsion. Diagnosis can usually be made with a careful history, physical examination and imaging studies, although definitive assessment may require arthroscopic evaluation. Tears are typically classified based on the extent of insertional compromise and the potential association with injury to the biceps tendon and/or remaining rotator cuff. Conservative management, consisting of activity restrictions and physical therapy, is generally limited to overuse tendinopathy and/ or partial-thickness tears. Complete tendon compromise warrants expedient operative fixation in most cases, through either an arthroscopic or an open approach. Limited outcome data suggest that after surgical intervention, athletes with isolated subscapularis tears do well, with most of them eventually returning to their preinjury level of sport.

REFERENCES

1. Yung SW, Lazarus MD, Harryman DT 2nd. Practical guidelines to safe surgery about the subscapularis. J Shoulder Elbow Surg 1996;5(6):467–70. 2. Klapper RC, Jobe FW, Matsuura P. The subscapularis muscle and its glenohumeral ligament-like bands. A histomorphologic study. Am J Sports Med 1992;20(3): 307–10. 3. Colas F, Nevoux J, Gagey O. The subscapular and subcoracoid bursae: descrip- tive and functional anatomy. J Shoulder Elbow Surg 2004;13(4):454–8. 4. Richards DP, Burkhart SS, Tehrany AM, et al. The subscapularis footprint: an anatomic description of its insertion site. Arthroscopy 2007;23(3):251–4. 5. Curtis AS, Burbank KM, Tierney JJ, et al. The insertional footprint of the rotator cuff: an anatomic study. Arthroscopy 2006;22(6):603–9. 6. D’Addesi LL, Anbari A, Reish MW, et al. The subscapularis footprint: an anatomic study of the subscapularis tendon insertion. Arthroscopy 2006;22(9):937–40. 7. Hunt SA, Kwon YW, Zuckerman JD. The rotator interval: anatomy, pathology, and strategies for treatment. J Am Acad Orthop Surg 2007;15(4):218–27. 8. Jost B, Koch PP, Gerber C. Anatomy and functional aspects of the rotator interval. J Shoulder Elbow Surg 2000;9(4):336–41. 9. Halder A, Zobitz ME, Schultz E, et al. Structural properties of the subscapularis tendon. J Orthop Res 2000;18(5):829–34. 10. Biondi J, Bear TF. Isolated rupture of the subscapularis tendon in an arm wrestler. Orthopedics 1988;11(4):647–9. 11. Dragoni S, Giombini A, Candela V, et al. Isolated partial tear of subscapularis muscle in a competitive water skier. A case report. J Sports Med Phys Fitness 1994;34(4):407–10. 12. Gerber C, Krushell RJ. Isolated rupture of the tendon of the subscapularis muscle. Clinical features in 16 cases. J Bone Joint Surg Br 1991;73(3):389–94. 13. Paschal SO, Hutton KS, Weatherall PT. Isolated avulsion fracture of the lesser tuberosity of the humerus in adolescents. A report of two cases. J Bone Joint Surg Am 1995;77(9):1427–30.

14. Levine B, Pereira D, Rosen J. Avulsion fractures of the lesser tuberosity of the humerus in adolescents: review of the literature and case report. J Orthop Trauma 2005;19(5):349–52. 15. Sugalski MT, Hyman JE, Ahmad CS. Avulsion fracture of the lesser tuberosity in an adolescent baseball pitcher: a case report. Am J Sports Med 2004;32(3): 793–6. 16. Sikka RS, Neault M, Guanche CA. An avulsion of the subscapularis in a skeletally immature patient. Am J Sports Med 2004;32(1):246–9. 17. Shah NN, Agarwal A, Turner R, et al. Avulsion of the lesser tuberosity with a Salter- Harris type II injury of the proximal humerus: a case report. J Shoulder Elbow Surg 2006;15(5):e16–8. 18. Sakurai G, Ozaki J, Tomita Y, et al. Incomplete tears of the subscapularis tendon associated with tears of the supraspinatus tendon: cadaveric and clinical studies. J Shoulder Elbow Surg 1998;7(5):510–5. 19. Kim TK, Rauh PB, McFarland EG. Partial tears of the subscapularis tendon found during arthroscopic procedures on the shoulder: a statistical analysis of sixty cases. Am J Sports Med 2003;31(5):744–50. 20. Bennett WF. Subscapularis, medial, and lateral head coracohumeral ligament insertion anatomy. Arthroscopic appearance and incidence of ‘‘hidden’’ rotator interval lesions. Arthroscopy 2001;17(2):173–80. 21. Nove-Josserand L, Levigne C, Noel E, et al. Isolated lesions of the subscapularis muscle. Apropos of 21 cases. Rev Chir Orthop Reparatrice Appar Mot 1994; 80(7):595–601. 22. Yoshikawa GI, Hori K, Kaneko H, et al. Acute subscapularis tendon rupture caused by throwing: a case report. J Shoulder Elbow Surg 2005;14(2):218–20. 23. Davis BA, Edwards JJ. Isolated subscapularis tear from minimal trauma in a recreational athlete: a case report. Arch Phys Med Rehabil 2001;82(12): 1740–3. 24. Neviaser RJ, Neviaser TJ, Neviaser JS. Concurrent rupture of the rotator cuff and anterior dislocation of the shoulder in the older patient. J Bone Joint Surg Am 1988;70(9):1308–11. 25. Lo IK, Burkhart SS. The etiology and assessment of subscapularis tendon tears: a case for subcoracoid impingement, the roller-wringer effect, and TUFF lesions of the subscapularis. Arthroscopy 2003;19(10):1142–50. 26. Paulson MM, Watnik NF, Dines DM. Coracoid impingement syndrome, rotator interval reconstruction, and biceps tenodesis in the overhead athlete. Orthop Clin North Am 2001;32(3):485–93, ix. 27. Gerber C, Terrier F, Ganz R. The role of the coracoid process in the chronic impingement syndrome. J Bone Joint Surg Br 1985;67(5):703–8. 28. Davidson PA, Elattrache NS, Jobe CM, et al. Rotator cuff and posterior-superior glenoid labrum injury associated with increased glenohumeral motion: a new site of impingement. J Shoulder Elbow Surg 1995;4(5):384–90. 29. Gerber C, Sebesta A. Impingement of the deep surface of the subscapularis tendon and the reflection pulley on the anterosuperior glenoid rim: a preliminary report. J Shoulder Elbow Surg 2000;9(6):483–90. 30. Habermeyer P, Magosch P, Pritsch M, et al. Anterosuperior impingement of the shoulder as a result of pulley lesions: a prospective arthroscopic study. J Shoulder Elbow Surg 2004;13(1):5–12. 31. Schickendantz MS, Ho CP, Keppler L, et al. MR imaging of the thrower’s shoulder. Internal impingement, latissimus dorsi/subscapularis strains, and related injuries. Magn Reson Imaging Clin N Am 1999;7(1):39–49.

32. Jobe FW, Moynes DR, Antonelli DJ. Rotator cuff function during a golf swing. Am J Sports Med 1986;14(5):388–92. 33. Ryu RK, McCormick J, Jobe FW, et al. An electromyographic analysis of shoulder function in tennis players. Am J Sports Med 1988;16(5):481–5. 34. Brasseur JL, Lucidarme O, Tardieu M, et al. Ultrasonographic rotator-cuff changes in veteran tennis players: the effect of hand dominance and comparison with clinical findings. Eur Radiol 2004;14(5):857–64. 35. Yanagisawa O, Niitsu M, Takahashi H, et al. Magnetic resonance imaging of the rotator cuff muscles after baseball pitching. J Sports Med Phys Fitness 2003; 43(4):493–9. 36. Iwamoto J, Takeda T, Ogawa K, et al. Muscle strain of the subscapularis muscle: a case report. Keio J Med 2007;56(3):92–5. 37. Pink M, Jobe FW, Perry J, et al. The painful shoulder during the butterfly stroke. An electromyographic and cinematographic analysis of twelve muscles. Clin Orthop Relat Res 1993;288:60–72. 38. Pink M, Jobe FW, Perry J, et al. The normal shoulder during the butterfly swim stroke. An electromyographic and cinematographic analysis of twelve muscles. Clin Orthop Relat Res 1993;288:48–59. 39. Flury MP, John M, Goldhahn J, et al. Rupture of the subscapularis tendon (isolated or in combination with supraspinatus tear): when is a repair indicated. J Shoulder Elbow Surg 2006;15(6):659–64. 40. Deutsch A, Altchek DW, Veltri DM, et al. Traumatic tears of the subscapularis tendon. Clinical diagnosis, magnetic resonance imaging findings, and operative treatment. Am J Sports Med 1997;25(1):13–22. 41. Barth JR, Burkhart SS, De Beer JF. The bear-hug test: a new and sensitive test for diagnosing a subscapularis tear. Arthroscopy 2006;22(10):1076–84. 42. Gerber C, Hersche O, Farron A. Isolated rupture of the subscapularis tendon. J Bone Joint Surg Am 1996;78(7):1015–23. 43. Burkhart SS, Brady PC. Arthroscopic subscapularis repair: surgical tips and pearls A to Z. Arthroscopy 2006;22(9):1014–27. 44. Tokish JM, Decker MJ, Ellis HB, et al. The belly-press test for the physical examination of the subscapularis muscle: electromyographic validation and comparison to the lift-off test. J Shoulder Elbow Surg 2003;12(5):427–30. 45. Zanetti M, Weishaupt D, Jost B, et al. MR imaging for traumatic tears of the rotator cuff: high prevalence of greater tuberosity fractures and subscapularis tendon tears. AJR Am J Roentgenol 1999;172(2):463–7. 46. Scheibel M, Martinek V, Imhoff AB. Arthroscopic reconstruction of an isolated avulsion fracture of the lesser tuberosity. Arthroscopy 2005;21(4):487–94. 47. Nove-Josserand L, Edwards TB, O’Connor DP, et al. The acromiohumeral and coracohumeral intervals are abnormal in rotator cuff tears with muscular fatty degeneration. Clin Orthop Relat Res 2005;433:90–6. 48. Farin P, Jaroma H. Sonographic detection of tears of the anterior portion of the rotator cuff (subscapularis tendon tears). J Ultrasound Med 1996;15(3):221–5. 49. Tung GA, Yoo DC, Levine SM, et al. Subscapularis tendon tear: primary and associated signs on MRI. J Comput Assist Tomogr 2001;25(3):417–24. 50. Li XX, Schweitzer ME, Bifano JA, et al. MR evaluation of subscapularis tears. J Comput Assist Tomogr 1999;23(5):713–7. 51. Goutallier D, Postel JM, Bernageau J, et al. Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan. Clin Orthop Relat Res 1994; 304:78–83.

52. Mellado JM, Calmet J, Olona M, et al. MR assessment of the repaired rotator cuff: prevalence, size, location, and clinical relevance of tendon rerupture. Eur Radiol 2006;16(10):2186–96. 53. Connor PM, Banks DM, Tyson AB, et al. Magnetic resonance imaging of the asymptomatic shoulder of overhead athletes: a 5-year follow-up study. Am J Sports Med 2003;31(5):724–7. 54. Bennett WF. Visualization of the anatomy of the rotator interval and bicipital sheath. Arthroscopy 2001;17(1):107–11. 55. Wright JM, Heavrin B, Hawkins RJ, et al. Arthroscopic visualization of the subscapularis tendon. Arthroscopy 2001;17(7):677–84. 56. Paribelli G, Boschi S. Complete subscapularis tendon visualization and axillary nerve identification by arthroscopic technique. Arthroscopy 2005;21(8):1016. 57. Nerot C, Jully JL, Gerard Y. Rotator cuff ruptures with predominant involvement of the subscapular tendon. Chirurgie 1993;119(8):404–10. 58. Pfirrmann CW, Zanetti M, Weishaupt D, et al. Subscapularis tendon tears: detection and grading at MR arthrography. Radiology 1999;213(3):709–14. 59. Kempf JF,Bonnomet F, Gleyze P, et al. Multicenter study of 210 rotator cuff ruptures treated with arthroscopic acromioplasty. Acta Orthop Belg 1995;61(Suppl 1): 23–31. 60. Edwards TB, Walch G, Nove-Josserand L, et al. Arthroscopic debridement in the treatment of patients with isolated tears of the subscapularis. Arthroscopy 2006; 22(9):941–6. 61. Richards DP, Burkhart SS, Campbell SE. Relation between narrowed coracohumeral distance and subscapularis tears. Arthroscopy 2005;21(10):1223–8. 62. Kragh JF Jr, Doukas WC, Basamania CJ. Primary coracoid impingement syndrome. Am J Orthop 2004;33(5):229–32 [discussion 232]. 63. Lo IK, Burkhart SS. The comma sign: an arthroscopic guide to the torn subscapularis tendon. Arthroscopy 2003;19(3):334–7. 64. Edwards TB, Walch G, Sirveaux F, et al. Repair of tears of the subscapularis. Surgical technique. J Bone Joint Surg Am 2006;88(Suppl 1 Pt 1):1–10. 65. Lyons RP, Green A. Subscapularis tendon tears. J Am Acad Orthop Surg 2005; 13(5):353–63. 66. Edwards TB, Walch G, Sirveaux F, et al. Repair of tears of the subscapularis. J Bone Joint Surg Am 2005;87(4):725–30. 67. Coates MH, Breidahl W. Humeral avulsion of the anterior band of the inferior glenohumeral ligament with associated subscapularis bony avulsion in skeletally immature patients. Skeletal Radiol 2001;30(12):661–6. 68. Burkhart SS, Tehrany AM. Arthroscopic subscapularis tendon repair: technique and preliminary results. Arthroscopy 2002;18(5):454–63. 69. Lafosse L, Jost B, Reiland Y, et al. Structural integrity and clinical outcomes after arthroscopic repair of isolated subscapularis tears. J Bone Joint Surg Am 2007; 89(6):1184–93.